Boy Scout contracts plague
August 26, 2008
The Wyoming Department of Health reports state health officials are investigating a case of bubonic plague in an out-of-state resident who recently visited Teton County and Yellowstone National Park.
The young adult traveled to multiple sites in the area with a group of Boy Scouts from July 26 to August 3, said Dr. Tracy Murphy, state epidemiologist with the Wyoming Department of Health.
"The individual traveled to Yellowstone National Park, Bridger-Teton National Forest and other sites within Teton County. He was involved in a combination of activities during his visit that included working on a service project, camping, sightseeing and participating in sports."
Wyoming Department of Health staff will participate in an environmental investigation with other agencies this week to look for fleas and animal carcasses in areas where the individual visited.
"At this time the exact location where the exposure to the disease occurred is not known and it is likely we will never determine that level of detail," Murphy said.
Dr. Karl Musgrave, state public health veterinarian with the Wyoming Department of Health, said that while the risk for humans to contract plague is relatively low in Wyoming, the disease has been documented in animals in 22 of Wyoming's 23 counties since records were kept.
This is the sixth human case of plague thought to be acquired in Wyoming since 1978. The most recent human case of plague in Wyoming was acquired in Goshen County in the fall of 2004. Other recorded cases involving residents include a 1978 Washakie County case, a 1982 Laramie County case, a 1992 Sheridan County case that resulted in death and a 2000 Washakie County case.
"Itís safe to assume that the risk for plague exists all around Wyoming," Musgrave said. "And while the disease is rare in humans, it is important that people take precautions to keep exposure to the disease to a minimum."
Ways to avoid the plague include:
- Avoiding unnecessary contact with rodents and their nests and burrows.
- Avoiding unnecessary contact with sick or dead animals, especially rodents and rabbits, and wearing protective gloves when handling sick or dead animals.
- Having ill pets, such as cats and dogs, examined by a veterinarian.
- Avoiding areas where a large number of unexplained rodent deaths have been observed.
- Keeping pets away from rodent nests and burrows by keeping them leashed.
- Treating pets with flea preventatives (see your local veterinarian for more information).
Murphy said that the typical sign of the most common form of human plague is a swollen and very tender lymph gland, accompanied by pain. The swollen gland is called a "bubo" (hence the term "bubonic plague"). Bubonic plague should be suspected when a person develops a swollen gland, fever, chills, headache, and extreme exhaustion and has a history of possible exposure to infected rodents, rabbits, or fleas. Murphy advised anyone experiencing these symptoms to see their healthcare provider.
Frequently Asked Questions about Plague (based on information from the Centers for Disease Control and Prevention):
Q. How is plague transmitted?
A. Plague, caused by a bacterium called Yersinia pestis, is transmitted from rodent to rodent by infected fleas.
Q. How do people get plague?
A. Plague is characterized by periodic disease outbreaks in rodent populations, some of which have a high death rate. During these outbreaks, hungry infected fleas that have lost their normal hosts seek other sources of blood, thus increasing the increased risk to humans and other animals frequenting the area. Rock squirrels and their fleas are the most frequent sources of human infection in the southwestern states. Other rodent species, such as prairie dogs, wood rats, chipmunks, and other ground squirrels and their fleas suffer plague outbreaks and some of these occasionally serve as sources of human infection. Deer mice and voles are thought to maintain the disease in animal populations but are less important as sources of human infection. Other less frequent sources of infection include wild rabbits, and wild carnivores that pick up their infections from wild rodent outbreaks. Domestic cats (and sometimes dogs) are readily infected by fleas or from eating infected wild rodents. Cats may serve as a source of infection to persons exposed to them. Pets may also bring plague-infected fleas into the home.
Q. What is the basic transmission cycle?
A. Fleas become infected by feeding on rodents, such as the chipmunks, prairie dogs, ground squirrels, mice, and other mammals that are infected with the bacteria Yersinia pestis. Fleas transmit the plague bacteria to humans and other mammals during the feeding process. The plague bacteria are maintained in the blood systems of rodents.
Q. Could you get plague from another person?
A. Yes, when the other person has plague pneumonia and coughs droplets containing the plague bacteria into air that is breathed by a non-infected person.
Q. What are the signs and symptoms of plague?
A. The typical sign of the most common form of human plague is a swollen and very tender lymph gland, accompanied by pain. The swollen gland is called a "bubo" (hence the term "bubonic plague"). Bubonic plague should be suspected when a person develops a swollen gland, fever, chills, headache, and extreme exhaustion, and has a history of possible exposure to infected rodents, rabbits, or fleas.
Q. What is the incubation period for plague?
A. A person usually becomes ill with bubonic plague two to six days after being infected. When bubonic plague is left untreated, plague bacteria invade the bloodstream. When plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition. Infection of the lungs with the plague bacterium causes the pneumonic form of plague, a severe respiratory illness. The infected person may experience high fever, chills, cough, and breathing difficulty, and expel bloody sputum. If plague patients are not given specific antibiotic therapy, the disease can progress rapidly to death.
Q. What is the mortality rate of plague?
A. About 14 percent (1 in 7) of all plague cases in the United States are fatal.
Q. How many cases of plague occur in the U.S.?
A. Human plague in the United States has occurred as mostly scattered cases in rural areas (an average of 10 to 20 persons each year). Globally, the World Health Organization reports 1,000 to 3,000 cases of plague every year.
Q. Is the disease seasonal in its occurrence?
A. No, plague can be acquired at anytime during the year.